Warren Widgeon of Antelope Camp in Susanville takes a break with his team after two days of firefighting on the Moonlight fire in Plumas National Forest near Greenville, Calif., Thursday, Sept. 6, 2007, which is now 28,000 acres and 8 percent contained. (AP Photo/The Bee, Anne Chadwick Williams) ** TV OUT, ONLINE OUT, MAGS OUT, NO SALES, MANDATORY CREDIT ** TV OUT, ONLINE OUT, MAGS OUT, NO SALES, MANDATORY CREDIT

Photo: Anne Chadwick Williams

Warren Widgeon of Antelope Camp in Susanville takes a break with...

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High winds from the north and east fanned the flames of the Moonlight Fire in the mountains of Plumas county, nearly doubling the area affected, 28,000 acres in all. Northerly winds pushed smoke southward through the Central Valley, and an inversion layer in the atmosphere trapped the smoke near the ground. Around the Bay Area, the winds shifted to a more easterly direction, allowing the smoke to stream out the Golden Gate and down the Bay. Smoke from the Lick Fire near Morgan Hill spread southward and brought Hazy conditions to the Salinas Valley and Monterrey Haze cleared out of many Bay Area locations in the afternoon as fog and westerly winds returned to the region. CR: NASA

(09-07) 09:38 PDT SAN FRANCISCO - Strong winds Thursday night pushed away most of the smoke that had drifted over the Bay Area from wildfires and prompted two days of air quality warnings.

Weather forecasters said some residual smoke remains over the region, however, and will take its time blowing away.

The smoke came from a 28,500-acre wildfire in Plumas County, about 200 miles northeast of San Francisco. Additionally, South Bay residents have been affected by a 27,640-acre wildfire in Henry W. Coe State Park, just east of Morgan Hill. Both fires have been burning since Monday.

Offshore winds had pushed smoke from the Plumas County blaze, dubbed the Moonlight Fire, into the Bay Area earlier this week, but the winds shifted direction Thursday afternoon and evening, said National Weather Service Forecaster Dan Gudgel. The shift helped air quality dramatically.

"There's some smoke still loitering in the area, but the source was cut off," Gudgel said this morning. "There is some residual smoke, and it will dissipate and move away - but slowly."

Gudgel said weather conditions will pretty much hold steady for the next week, limiting the chances that more smoke will drift south into the region. Temperatures will remain seasonal, he added.

There is a thick marine layer blanketing the coast and some inland areas this morning. Although the cool, damp air helps crews battling the Lick Fire in Santa Clara County, low-hanging fog and smoke mean air tankers and helicopters can't help out, said Henry DeKruyff, a spokesman for the state Department of Forestry and Fire Protection.

Air support was also called off Thursday because of the poor visibility.

"When it's clear they can get in, but we have one helicopter right now over it, and the pilot says there is still too much smoke and some fog," DeKruyff said this morning.

Firefighters have been concentrating their efforts on the ground, digging fire lines and setting some backfires to help bring the blaze under control. It grew about 600 acres overnight and remains about 35 percent contained.

Ground efforts could also be hampered, DeKruyff said, because the one road into the park is deteriorating from the heavy fire engines and bulldozers that have been traveling back and forth since Monday.

"They are starting to wear down the road big time," he said.

Authorities believe the blaze was caused by an illegal trash burn. About 25 residences, 10 outbuildings and several campgrounds remain evacuated. One outbuilding has been destroyed.

Meanwhile, fire crews at the Moonlight Fire near Greenville have managed to keep the fire away from about 500 homes in the area. The blaze is 8 percent contained, and its cause is under investigation.